Bit retaining system for rotary tool

ABSTRACT

A bit retaining system for a rotary tool or device such as a router is disclosed. The bit retaining system may include a collet assembly and a control assembly. The collet assembly may include a spindle, a collet adapted to receive the bit, and a collet nut. The collet assembly may further include a collet gear mounted on the collet nut and/or a spindle gear mounted on the spindle. The control assembly selectively engages the collet assembly to drive the collet nut and/or secure the spindle in a fixed position, preventing its rotation. In operation, a hand tool is utilized to engage the control assembly. This configuration enables a user to capture and release the rotary tool bit using one hand.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent ApplicationNo. 61/207,675, filed on Feb. 13, 2009, and entitled “Router”, and U.S.patent application Ser. No. 12/706,288, filed Feb. 16, 2010, now U.S.Pat. No. 8,678,725, entitled “Router”; and U.S. patent application Ser.No. 14/189,021 filed Feb. 25, 2014, now U.S. Pat. No. 9,238,270,entitled “Bit Retaining System for Rotary Tool”. The disclosures ofwhich are hereby incorporated by reference in their entirety.

FIELD OF THE INVENTION

The present invention is directed toward a system for releasablysecuring a cutting tool to a rotary device and, in particular, to a bitretaining system that secures a bit to a router.

BACKGROUND OF THE INVENTION

Rotary tools, such as drills or routers, include a tool retainer orholder that non-rotatably secures a rotary bit (e.g., a cutting toolsuch as a drill bit or a router bit) to a driving device that rotates adrive shaft. The rotation of the drive shaft causes a correspondingrotation of the rotary bit; consequently, the clamping force of theretainer must provide sufficient gripping action of the bit. Otherwise,the bit will slip in its holder, resulting in poor tool performance, aswell as creating a hazard to those working near the tool.

Bit retainer systems for woodworking, metalworking, and the like havebeen developed. Common types of bit holders include collet systems orchucks. Collets require a substantial amount of torque to be exerted ona threaded retainer or spindle in order to attain sufficient clampingforce on the bit. This preloads the system such that the frictionalengagement between the collet and the cutting tool limits movementtherebetween.

FIG. 1 is a perspective view of a rotary tool 100 (e.g., a router)including a conventional bit retaining system. As shown, the rotary tool100 includes a motor housing 105, a bit retaining assembly 110, andspindle lock assembly 115. The bit retaining assembly 110 includes aspindle 120 with a collet 125, and a collet nut 130 threadingly engagingthe spindle 120. Rotating the collet nut 130 displaces the nut along thespindle axis, which, in turn, narrows and widens the opening of thecollet 125.

The spindle lock assembly 115 selectively secures the spindle 120 toenable the rotation of the collet nut 130. Engaging an actuator 140activates a lock that prevents the rotation of spindle 120, which inturn, permits the rotation of the collet nut 130 with respect to thespindle 120. In operation, a user first engages the lock assemblyactuator 140 with one hand to secure spindle 120. Using a second hand,the user rotates the collet nut 120 with a wrench to widen (loosen) ornarrow (tighten) the collet to remove or secure the bit as needed.

Thus, when changing the bit of a router, it is necessary to utilize twohands—one to engage the locking mechanism and one to tighten or loosenthe bit within a router collet. It is often desirable to quickly attachthe bit to the rotary tool or to quickly remove the bit from the tool.For example, several router bits may be needed throughout the course ofshaping a single work piece with a router; consequently, it would bedesirable to change the bits quickly and efficiently. This process ofutilizing multiple hands for changing the bits is inefficient and thusundesirable because of the additional time and effort required forattaching the bits to and removing the bits from the collet.Furthermore, in order to attain the high torque necessary to achieveproper clamping force collet systems typically require the use of a nutwrench that rotates the collet nut to release or capture the bit. Thisuse of conventional wrenches to displace the collet nut is not onlycumbersome, but often proves ineffective since the effective clampingforce is dependent on the torque applied by the individual operator,which varies from one person to another.

Therefore, there is a need for a bit retaining system for a rotary toolthat is operated utilizing a single hand, and which provides adequatetorque to non-rotatably retain a cutting tool (such as a router bit)with minimal force applied by an operator.

SUMMARY OF THE INVENTION

The present invention is directed to a bit retaining system for a rotarytool such as a router. In one embodiment, the bit retaining systemincludes a collet assembly and a control assembly. The collet assemblyincludes a spindle, a collet mounted in the spindle that is adapted toreceive a bit, and a collet nut that alters the internal dimensions ofthe collet to capture the bit therein. The collet assembly may furtherinclude a collet gear mounted on the collet nut and/or a spindle gearmounted on the spindle. The control assembly selectively engages thecollet assembly to drive the collet nut relative to the spindle. Inoperation, a hand tool is utilized to engage the control assembly. Abias member biases an engagement portion of the control assembly awayfrom the collet assembly. However, the engagement portion is engagedwith the collet assembly when the user urges the tool to overcome thebias force. A turning force is simultaneously applied to the urgingforce to cause relative rotation of the spindle and collet nut. Thisconfiguration enables a user to capture and release the rotary tool bitusing one hand.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a perspective view of a rotary tool including aconventional bit retaining system.

FIG. 2 illustrates a perspective view of a rotary tool including a bitretaining system in accordance with an embodiment of the invention.

FIG. 3 illustrates an isolated, cross sectional view of the colletassembly shown in FIG. 2, with the collet and spindle gears removed forclarity.

FIG. 4A illustrates the bit retaining system shown in FIG. 2 with thehousing removed for clarity, showing a perspective view of the colletassembly.

FIG. 4B illustrates the bit retaining system of FIG. 2 with the housingremoved for clarity, showing the assembly of FIG. 4A and a control gearfrom the control assembly.

FIG. 5A illustrates the bit retaining system of FIG. 2, with a portionof the housing removed for clarity, showing the control gear disengagedfrom the gears of the collet assembly.

FIG. 5B illustrates the bit retaining system of FIG. 2, with a portionof the housing removed for clarity, showing the control gear engagedwith the gears of the collet assembly.

FIG. 5C illustrates the bit retaining system of FIG. 2, showing theoperation of the system utilizing a hand operated tool.

FIG. 6A illustrates a perspective view of a rotary tool including a bitretaining system in accordance with another embodiment of the invention.

FIG. 6B illustrates the bit retaining system of FIG. 6A, with a portionof the housing removed for clarity.

FIGS. 7A, 7B and 7C illustrate front views of the bit retaining systemof FIG. 6A with a portion of the housing removed, showing the operationof the system. Specifically, FIG. 7A illustrates the displaceable gearin its normal, disengaged position, while FIGS. 7B-7C show thedisplaceable gear in its engaged position in which it meshes with thecollet gear.

FIG. 8 illustrates a perspective view of a rotary tool including a bitretaining system in accordance with another embodiment of the invention.

FIG. 9A illustrates the bit retaining system of FIG. 8, with a portionof the housing removed for clarity, showing the control assemblydisengaged from the collet assembly.

FIG. 9B illustrates the bit retaining system of FIG. 8, with a portionof the housing removed for clarity, showing the control assembly engagedwith the collet assembly.

FIG. 9C illustrates a close-up view of the control assembly shown inFIGS. 9A and 9B.

FIGS. 10A and 10B illustrate isolated views of a bit retaining system inaccordance with another embodiment of the invention.

FIG. 11 illustrates isolated views of a bit retaining system inaccordance with another embodiment of the invention.

FIG. 12 illustrates a worm actuator of the bit retaining system as shownin FIG. 11.

FIG. 13 illustrates a worm actuator of the bit retaining system as shownin FIG. 11, in a disengaged arrangement.

FIG. 14 illustrates an enlarged view of the worm actuator of the bitretaining system as shown in FIG. 11.

Like reference numerals have been used to identify like elementsthroughout this disclosure.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 2 and 3 illustrate a rotary tool including a bit retaining systemin accordance with an embodiment of the present invention. Referring toFIG. 2, the rotary tool 200 (e.g., a router) with a motor housing 205and a bit retaining system 210 including a collet assembly 215 inselective communication with a control assembly 220 disposed in a systemhousing 222. Referring to FIG. 3, the collet assembly 215 includes aspindle 305, a collet 310, and collet nut 315. The spindle 305, whichmay generally define a right cylinder, extends distally from the motorhousing 205 from a generally centrally location thereon. The distalportion of the spindle 305 is externally threaded to engagecomplementary threads on the collet nut 315.

The spindle 305 defines an interior channel 322 that tapers radiallyinward in the direction of the motor housing 205 to define a spindlechannel having a generally frustoconical shape. The collet 310 isreceived in the channel 322 such that it is generally coaxial with thespindle 305. The collet 310 includes a plurality of fingers 325 havingslots 327 formed therein. The fingers 325 define a generally cylindricalbore or opening 330 operable to receive the shank portion of a bit(e.g., a router bit). The collet 310, moreover, is adapted to moveaxially into and out of the spindle channel 322. With thisconfiguration, drawing the fingers 325 outward (axially out of thechannel 322) widens the diameter of the bore 330 by expanding the slot327. Conversely, drawing the fingers 325 inward (axially into thespindle channel 322) narrows the diameter of the bore 330 by compressingthe slot 327. In this manner, the fingers 325 may be compressed toprovide adequate clamping force secure a bit within the tool.

The spindle 305 is coupled to the rotor of the motor by an armatureshaft 307. By way of example, the spindle 305 may be fixedly connectedto the shaft 307 via a pin, screw, etc. Specifically, the spindle andshaft 307 rotate coaxially about a generally vertical spindle axis SA.

The collet nut 315 includes a side wall 350 and an upper wall or flange355 defining a generally annular opening that permits passage of thecollet 310 and the bit shank therethrough. The collet nut 315 axiallycaptures the collet 310 within the spindle 305. For example, the flange355 of the collet nut 315 may engage shoulders 360 and/or tabs 365formed into the outer surface of the collet 310. Alternatively, thecollet 310 may include a notch formed into the collet perimeter thatreceives the end of flange 355 extending from the collet side wall 350.The collet nut 315 is internally threaded with threads complementary tothe threads formed on the surface of the spindle 305. Consequently,rotating the collet nut 315 about the spindle axis displaces the nutaxially along the longitudinal axis of the spindle 305 (indicated byarrows A).

With the above described configuration, rotating the collet nut 315 inone direction drives the nut toward the distal end of the spindle 305.The collet nut 315 engages the tabs 365 to draw the collet 310 axiallyoutward from the spindle channel 322. Conversely, rotating the colletnut 315 in an opposite direction draws the collet nut 315 toward thespindle proximal end. The collet nut 315 engages the shoulders 360axially urge the collet 310 inward, into the spindle channel 322. Asnoted above, drawing the collet 310 into and out of the spindle channel322 alters the diameter of the collet bore 330, widening and narrowingthe collet bore to selectively secure and release the shank of the bit.

Referring to FIG. 4A, the collet assembly 215 further includes a spindlegear 400 and a collet gear 410 that cooperate with the control assembly220 to selectively engage and disengage the shank of a bit positionedwithin the collet. As shown, the spindle gear 400 is longitudinallyspaced from the collet gear 410 along the spindle 305, with each gearbeing generally coaxial with the spindle. The spindle gear 400 may befixedly attached to or integral with the spindle 305, and may be in theform of a generally annular bevel gear having a plurality of teeth 405disposed about the circumference of the spindle, and oriented to faceaway from the motor housing 205 (i.e., toward the collet gear 400).Alternatively, the spindle gear 400 may be fixed to motor housing 205with spindle 305 rotatable therein. Similarly, the collet gear 410 maybe fixedly attached to or integral with the collet nut 315, and may bein the form of a generally annular bevel gear having a plurality ofteeth 415 disposed about the circumference of the collet nut 315, andoriented to face toward the motor housing 205 (i.e., toward the spindlegear 400). The spindle gear 400 and the collet gear 410 may possess thesame number of teeth 405, 415, as well as the same tooth geometry andsize.

The control assembly 220 is configured to selectively engage the gears410, 400 of the collet assembly 215 and, in particular, to drive therelative rotation of the spindle 305 and collet nut 315. Referring toFIG. 4B, the control assembly 220 includes a laterally displaceablecontrol gear 430 adapted to selectively engage the spindle gear 400 andcollet gear 410. Specifically, the control gear 430 may be in the formof a bevel gear having a generally frustoconical head portion 435 withteeth 440 proportionally sized to simultaneously mesh with the teeth 405of the spindle gear 400 and the teeth 415 of the collet gear 410. Theoverall dimensions of the head portion 435 of the control gear 430 maybe smaller or larger than that of the spindle gear 400 and the colletgear 410 to improve torque generation.

A generally cylindrical shaft 445 extends distally from the head portion435. A socket 450, disposed at the shaft distal end, is configured toreceive a hand operated tool. By way of example, the socket 450 may inthe form of a shaped receptacle that is keyed to receive a tool such asa hex wrench. A biasing member 455 (e.g. a compression spring) iswrapped around an intermediate portion of the shaft 440, being capturedbetween a lip 465 defined by the head portion 435 and a shoulder 470defined by the socket 450.

Referring to FIGS. 5A and 5B, the system housing 222 includes a cavity510 that constrains the lateral movement of the control gear 430.Specifically, the cavity 510 is defined by a first or forward wall 515and a second or rearward wall 520. The first wall 515 includes anopening that is generally aligned with an opening in the second wall520. The openings permit the shaft 445 of the control gear 430 to slidewithin the cavity 510 toward and away from the spindle 400 and colletgears 410. Specifically, the control gear 430 is configured to movelaterally along a generally horizontal control gear axis that isoriented generally orthogonal to the generally vertical spindle axis SAto selectively engage and disengage the spindle gear 400 and collet gear410. In addition, the openings permit the control gear 430 to rotateabout the control gear axis.

This axial movement of the control gear 430 is constrained byinteraction between the walls 515, 520 of the cavity 510 and the lip 465and shoulder 470 portions of the control gear 430. That is, the firstwall 515 functions as a stop, preventing the forward/inward movement ofshoulder 470 of control gear 430. Similarly, the second wall 520functions as a stop, preventing the rearward/outward movement of thecontrol gear 430 beyond the lip 465 defined by the head portion 435.With this configuration, the control gear 430 may be displaced along itsaxis toward the spindle 305 by applying a force sufficient to overcomethe biasing force applied by the biasing member 455. Biasing member 445is disposed between wall 515 and shoulder 470 to biases control gear 430back into a rest position away from collet assembly 215.

Specifically, the control gear 430 may be selectively moved from afirst, disengaged position, to a second, engaged position. The operationof the device is explained with reference to FIGS. 5A, 5B, and 5C. Thecontrol assembly 215 begins in is normal, disengaged position (FIG. 5A).That is, the biasing member 455 biases the control gear 430 outward suchthat the teeth 440 of the head portion 435 are not meshed with the teeth405 of the spindle gear 400 or with the teeth 415 of the collet gear410. As a result, the spindle 305 may be rotated by the motor withoutaffecting the security of the bit within the bit retaining assembly.

To tighten or loosen the collet 310, a hand operated tool 530 (e.g., ahex wrench) is inserted into the socket 450. Specifically, the handoperated tool is inserted axially into the socket 450, along the controlgear axis oriented generally perpendicular to the spindle axis SA. Thetool is utilized to apply a horizontal force to control gear 430 thatovercomes the biasing force of the biasing member 455 (FIG. 5C). Theforce drives the control gear 430 laterally along the control gear axisuntil the teeth 440 on the head portion 435 are in meshed engagementwith the teeth 405, 415 of the spindle gear 400 and collet gear 410,respectively (FIG. 5B). Once meshed, the hand operated tool 530 isrotated, which, in turn, rotates the control gear 430 about the controlgear axis. Rotating the hand operated tool 530 causes the spindle gear400 and the collet gear 410 to rotate in opposite directions about thespindle axis SA. For example, the collet gear 410 may rotate in aclockwise direction while the spindle gear 400 rotates in a counterclockwise direction (and vice versa). Consequently, the spindle 305 isrotated in a first direction (via the spindle gear 400) while the colletnut 315 rotates in the opposite direction (via the control gear 410). Inthis manner, the collet nut 315 is driven axially along the spindle 305to expand or compress the fingers 325 as described above.

FIGS. 6A and 6B illustrate a rotary tool including a bit retainingsystem in accordance with another embodiment of the invention. Asillustrated, the rotary tool 600 includes a bit retaining system 602including a collet assembly 605 and a transmission assembly 610 disposedon housing 205. The collet assembly 605 includes spindle 615, a collet620 formed of fingers 625, and a collet nut 630. The spindle 615, whichmay be in communication with a motor housed in the motor housing 205, isconfigured to rotate about a central axis (also called a spindle axisSA, seen best in FIG. 7A). As in the assembly described above, thecollet nut 630 threadingly engages the spindle 615 such that the colletnut moves axially along the spindle 615, selectively altering thediameter of the collet bore 330 based upon its longitudinal position onthe spindle. The collet nut 630 further includes a plurality of teeth635 extending radially from its exterior surface, about thecircumference of the nut, to define a collet gear 640.

The transmission assembly 610 includes a control gear 645 meshed with arepositionable intermediate gear 650, as well as a carriage assembly652. The control gear 645 may be a generally annular spur gear includingteeth 655 extending about the gear periphery. The control gear 645further includes a central socket 660 in the form of a shaped receptacleconfigured to receive and frictionally engage a hand operated tool (seenin FIGS. 7A and 7B). For example, the socket 660 may be a receptaclehaving a generally hexagonal cross section that engages a hex key. Thesocket 660 defines a central channel that passes completely through thecontrol gear 645, permitting the key to extend axially therethrough. Theentrance to the socket 660 may further include lead-in chamfers to guidekey into the socket. The control gear 645 is adapted to rotate about acentral axis (also called a control gear axis) that is orientedgenerally parallel to the spindle axis SA.

The intermediate gear 650 may be a generally annular spur gear includingteeth 662 adapted to engage not only the teeth 655 of the control gear645, but also the teeth 635 of the collet gear 640. As shown in thefigures, the height/thickness of the intermediate gear 650 may be abouthalf the height of the control gear 645. The intermediate gear 650rotates about a central axis (also called an intermediate gear axis)that is oriented generally parallel to the spindle axis SA.

In addition, the intermediate gear 650 is repositionable along thecentral intermediate gear axis such that it selectively engages anddisengages the collet gear 640. Specifically, the intermediate gear 650is mounted on a yoke or axle 670 extending through the center apertureof the gear. The yoke 670 includes an elongated slot 672 through which asupport rod 675 passes. The support rod 675, oriented below theintermediate gear 650, is oriented substantially orthogonal to thecentral axis of the intermediate gear 650. The support rod 675 isconfigured to move along the slot 672, supporting the intermediate gear650 as it travels from a first/lower slot position to a second/upperslot position, and vice versa. A biasing member 677 (e.g., a compressionspring) is seated within an annular recess 678 formed into theintermediate gear 650. The biasing member 677 biases the intermediategear 650 in a normal, disengaged position in which the intermediate gearis not oriented in the same plane as the collet gear 640.

The transmission assembly 610 further includes a shift fork 679 thatselectively drives the intermediate gear 650 into engagement with thecollet gear 640. Specifically, the shift fork 679 has a generallyU-shaped structure defined by a transverse bar or ramp 680 and a pair ofrails 682 extending outward from the transverse bar 680. Each rail 682includes a depression 685 that cradles the support rod 675. The shiftfork 679 is pivotally coupled to the carriage assembly 652 along a pivotpoint P to define a pivot axis that is oriented generally orthogonal toone or more of the gear axes. With this configuration, applying adownward pressure to the transverse bar 680 generates a counterclockwiserotation in the shift fork 679 (from the viewpoint of FIG. 7A), whichmoves the rail 682 upward to drive the intermediate gear 650 upwardalong the yoke 670, against the biasing force of the biasing member 677.Upon release of the pressure, the biasing member 677 drives theintermediate gear 650 back to its normal position.

The operation of the device is explained with reference to FIGS. 7A, 7Band 7C. The bit retaining system initially begins in its normal,disengaged position (FIG. 7A). In this position, the intermediate gear650, while meshed with the control gear 645, is disengaged from thecollet gear 640. As a result, the collet assembly 605 is free to rotate(driven by the motor) without altering the compression force applied bythe collet 620. A hand operated tool 700 (e.g., a tool operable to applytorque such as a hex key) is inserted through the opening of the socket660. Specifically, the hand operated tool 700 is inserted into thecontrol gear along an axis that is generally parallel to the spindleaxis SA. This axial insertion of the hand operated tool 700 causes theend 710 of the tool to contact the transverse bar 680 of the shift fork679, pivoting the rail 682 upward as described above. This, in turn,drives the intermediate gear 650 upward along its central axis and intomeshed engagement with the collet gear 640. The hand operated tool 700may be inserted through the control gear 645 until it engages a carriageshoulder 715 that functions as a stop, preventing over insertion of thetool. The tool may also include a recess 716 into which the transversebar 680 is seated when the tool 700 is properly positioned within thesocket 660. Once engaged, torque from the hand operated tool 700 can betransferred to the collet gear 640. Since the intermediate gear 650 isaligned with the collet gear 640 in the engaged position, rotating thecontrol gear 645 about its central axis rotates the intermediate gear650 about its central axis. This, in turn, rotates the collet gear 640and the attached collet nut 630 about the spindle axis SA.

If the spindle 615 is not secured from rotation, rotating the handoperated tool 700 will also rotate the spindle, preventing the rotationof the nut 630 with respect to the spindle. Thus, in addition torepositioning the intermediate gear 650, the shift fork 679 furtheractivates a spindle lock mechanism that secures the spindle 615 toprevent its rotation. Referring to FIG. 7A, the carriage assembly 652further includes a C-shaped, translating sled 720 that houses agenerally cylindrical pin 725 having a proximal end 727 and a distal end728. The proximal end 727 of the pin 725 is coupled to a first biasingmember or extension spring 730 that biases the pin toward the spindle615. In addition, the intermediate portion of the pin 725 is coupled toa second biasing member or retraction spring 735 seated within anannular recess 737 formed around a window 738.

In the disengaged position (i.e., when the hand operated tool 700 is notcompletely engaged with the shift fork), the retraction spring 735drives the pin 725 away from the spindle 615, orienting the sled 720 inspaced relation from the window 738. Inserting the hand operated tool700 into engagement with the transverse bar 680 of the shift fork 679drives the sled 720 forward to overcome the biasing force of theretraction spring 735 (since the extension spring 730 is stiffer thanthe retraction spring 735). That is, the sled 720 is driven toward thewindow 738 by the shift fork 679 when engaged The sled 720 acts upon theextension spring 730 which, in turn, acts upon the pin 725, driving ittoward the spindle 615 and compressing the retraction spring 735 as seenin FIG. 7B. The retraction spring 735 ensures that pin 725 never extendsinto notch 740 when the tool is turned on (i.e., the rotor is powered tooperate).

As a result, the pin 725 passes through the window 738, contacting thespindle 615. The spindle 615 includes one or more notches 740 that areadapted to receive the distal end 728 of the pin 725. If the notch 740is not aligned with the pin 725, the extension spring 730 flexes(compresses) to prevent damage to the spindle 615 (as seen in FIG. 7C).To align one of the notches 740 with the pin 725, the user simplyrotates the hand operated tool 700, which causes the spindle 615 torotate as explained above due (e.g., to friction between the threads ofthe collet nut 315 and the spindle 615). Once aligned, the pin 725 isurged into the notch 740 by the extension spring 730. When positionedwithin the notch 740, the rotational position of the spindle 615 isfixed, thereby preventing spindle rotation about the spindle axis SA.Any additional torque applied to the control gear 645 will rotate thecollet gear (and thus the collet nut), but not the spindle 615.

Thus, once the hand operated tool 700 is fully engaged with the shiftfork 679, the spindle 615 is secured in a fixed position by theengagement of the pin 725 with the notch 740. The hand operated tool 700is then rotated, thereby rotating the control gear 645. The rotarymotion of the control gear 645 is transferred through the intermediategear 650 to the collet gear 640. This rotation causes the axial movementof the collet nut 630 along the spindle 615, which, in turn, compressesor releases the collet 620 to tighten or loosen its hold on the shank ofa rotary tool bit as described above.

Upon removal of the hand operated tool 700, the retraction spring 735drives the pin 725 and the sled 720 away from the spindle 615. The pin725 is drawn out of the notch 740 and the sled 700 is returned to itsnormal position. The above described configuration provides a bitretaining assembly with one-handed operation, since the hand operatedtool simultaneously locks the spindle and rotates the collet nut toexpand or constrict the collet. In addition, this configuration permitsa user to insert the hand operated tool 700 along an axis that isgenerally parallel to the spindle axis SA (i.e., the axis of spindlerotation), which is typically easier for the user.

FIGS. 8, 9A, 9B, and 9C illustrate a bit retaining system in accordancewith another embodiment of the invention. Referring to FIG. 8, a rotarytool 800 includes bit retaining system 810 including a collet assembly820 and a control assembly 830 disposed within a housing 840. As shownin FIGS. 9A-9C, the collet assembly 820 may include a generallycylindrical spindle 905 extending distally from the motor housing 205that rotates about a generally vertical spindle axis. As with the aboveembodiments, the collet assembly 820 includes an internally threadedcollet nut 910 that engages the external threads formed on the perimeterof the spindle 905. Furthermore, a collet 915 is mounted within thespindle 905. The collet 915 includes fingers 917 adapted collapse andexpand depending on the axial position of the collet nut 910 withrespect to the spindle 905, as described above.

A collet gear 920 is attached to or integrated with the collet nut 910.The collet gear 920 may be a generally annular spur gear including aplurality of teeth 925, extending radially from the collet nut 920, thatare spaced about the collet nut circumference. A spindle gear 930 islongitudinally spaced from the collet gear 920 such that it is locatedproximate the motor housing 205. The spindle gear 930, which is attachedto or otherwise integrated into the spindle 905, may be a generallyannular spur gear including a plurality teeth 935 extending radiallyfrom the spindle 905, which are spaced about the spindle circumference.As shown, the gears 920, 930 are generally coaxial with the axis of thespindle 905.

The control assembly 830 includes a displaceable carriage or sled 940slidingly mounted on a support post 945 (support shown in cross sectionin FIGS. 9A-9C). The support post includes a plurality ofcircumferentially spaced guide notches 947 running axially along thepost. The carriage 940 includes a base 950 and a series of legs 952extending distally (upward from the viewpoint of FIG. 9A) from the base.The legs 952 are configured to slide along the guide notches 947. In oneembodiment, the lateral dimensions of the legs 952 may be slightlysmaller than the width of the guide notches 947. This permits slightrotational movement of the carriage 940 with respect to the support 945.By way of example, the carriage 940 may rotate the angle of one geartooth when turned by a tool. This permits automatic adjustment of thegear positions to provide alignment. Alternatively, a user may manuallyrotate the carriage 940 to align the gears. The carriage 940 is biasedtowards a normal, disengaged position by a biasing member 955 (e.g., acompression spring). With this configuration, the carriage 940 ridesaxially along the support post 945, being biased toward normal position.

The carriage 940 further includes a tab 960 extending radially from thebase 950 that is configured to mesh with the teeth 935 of the lockinggear 930. In addition, the carriage 940 includes a control gear 965supported on the legs 952 that is adapted to rotate with respect to thecarriage 940. Specifically, the carriage 940 remains in a generallyfixed rotational position while the control gear 965 rotates about anaxis generally aligned with the axis of the support post 945. Thecontrol gear 965 includes a plurality of teeth 967 adapted to mesh withthe teeth 920 of the collet gear 925.

The control assembly 830 further includes a guide socket 970 that leadsto a key or receptacle 975 in communication with the control gear 965.The receptacle 975 may be keyed to mate with a hand tool such as a lugwrench. With this configuration, mating a tool with the receptacle 975and rotating the tool causes a corresponding rotation of the controlgear 965.

The operation of the device is explained with reference to FIGS. 9A and9B. The control assembly 830 begins in its first, normal position, inwhich the carriage 940 is positioned such that the locking tab 960 onthe base 950 is disengaged from the teeth 935 of the spindle gear 930(FIG. 9A). In addition, in the normal position, the control gear 965does not lie in the same plane as the collet gear 920; consequently, thegears 920, 965 are not meshed when the carriage 940 is in its normalposition and the hand operated tool 800 is permitted to rotate withoutaffecting the securing of the bit within the collet. A hand operatedtool 980 operable to apply torque is inserted axially into the guidesocket 970 until it engages and becomes properly seated on thereceptacle 975. The hand operated tool 980 is urged axially, toward themotor housing 205. This, in turn, overcomes the biasing force applied tothe carriage 940 by the biasing member 955, driving the carriage 940toward the motor housing 205 (FIG. 9B).

As the carriage 940 is driven toward the motor housing 205, the carriage940 may automatically rotate a predetermined amount to properly seat thetab 960 extending radially from the base 950 between adjacent teeth 935on the spindle gear 930 (described above). Alternatively, the user mayslightly rotate the hand operated tool 980 to align the gear teeth. Whenthe carriage 940 reaches its lowermost position, the tab 960 meshes withthe teeth 935 of the spindle gear 930. In addition, the teeth 967 of thecontrol gear 965 mesh with the teeth 925 of the collet gear 920.Rotating the tool 980 causes a corresponding rotation in the controlgear 965, which, in turn, rotates the collet. Since the base 950 isrotationally fixed, the tab 960 secures the spindle gear 930, preventingthe rotation of the spindle 905. The collet nut 910, however, rotates,since the rotation of the control gear 965 (created by the toolrotation) is transferred to the collet nut 910. As a result, the colletnut 910 moves axially along the spindle 905, collapsing and expandingthe collet 915, securing or releasing a bit shank within the collet.

FIGS. 10A and 10B illustrate a bit retaining system in accordance withanother embodiment of the invention. The bit retaining system 1000 is asingle spur gear configuration including a collet assembly 1005 and acontrol assembly 1010. The collet assembly 1005 includes a spindle 1015with a collet 1020, as well as a collet nut 1025 that threadinglyengages the spindle in a manner similar to that described above. As aresult, the axial movement of the collet nut 1025 along the spindle 1015(caused by the rotational movement between the collet nut and thespindle) selectively expands and collapses the collet 1020 toengage/disengage the shank of a bit. A collet gear 1030 may be attachedor integrated into the collet nut 1025. The collet gear 1030 may be inthe form of a spur gear including a plurality of teeth 1035 extendingradially from collet nut and spaced about the collet nut circumference.

The collet assembly 1005 further includes a spindle gear 1040 attachedor otherwise integrated into the spindle 1015, disposed at a locationthat is axially spaced from the collet gear 1030. The spindle gear 1040may be in the form of a generally annular spur gear having a pluralityof teeth 1042 extending radially from the spindle 1015 and spaced aboutthe spindle perimeter. With this configuration both the upper colletgear 1030 and the lower spindle gear 1040 rotate as the spindle isrotated by the motor.

The control assembly 1010, adjacent the collet assembly 1005, includes agenerally cylindrical shaft 1045 including a carriage 1050 adapted tomove axially along the shaft. The carriage 1050 includes a first orupper section 1052 and a second or lower section 1055. The sections1052, 1055 are constrained axially to one another along a frictionsurface. The upper section 1052 includes a control gear 1060 that isfree to rotate about the axis of the carriage 1045. The control gear1060 may be in the form of a spur gear including a plurality of teeth1062 extending radially from the carriage 1050. The lower section 1055,furthermore, includes at least one tab or gear tooth 1065 extendingradially from the carriage 1050.

The carriage 1050 is biased in a normal position (e.g., biased such thatthe carriage is spaced from the motor housing) by a biasing member 1070such as a spring. In particular, the biasing member 1070 positions thecarriage 1050 such that, in the carriage normal position, neither thecontrol gear 1060 nor the tab 1065 are meshed with the collet gear 1030or the spindle gear 1040, respectively. That is, in the normal position,the control gear 1060 disposed on the first section 1052 of the carriage1050 is not in the same plane as the collet gear 1030. Similarly, thetab 1070 disposed on the second section 1055 of the carriage 1050 doesnot lie in the same plane as the spindle gear 1040.

The control assembly 1010 is configured such that urging the carriage1050 axially toward the motor housing (downward from the perspective ofFIG. 10A) overcomes the biasing force of the biasing member 1070 andaligns the control gear 1060 with the collet gear 1030 and the tab 1065with the spindle gear 1040 (discussed in greater detail below).

The lower section 1055 of the carriage 1050 may further include aninternal key 1075 that permits limited rotation of the lower sectionwith respect to the shaft 1045. With this configuration, the tab 1065 ofthe lower section 1050 is adapted to rotate by only the angle necessaryto mesh it with the spindle gear 1040. By way of example, the rotationof the lower section 1055 about the shaft 1045 may be limited to aboutless than 10 degrees. By way of further example, the lower section 1055may rotate the angle of one gear tooth. The friction surface 1047between the upper section 1052 and the lower section 1055 transmitstorque applied to the upper section through to the lower section inorder to align the tab 1065 on the lower section with the spindle gear1040 on the spindle 1015. With this configuration, the substantialrotation of the spindle 1015 is prevented, but the tab 1070 may beslightly adjusted to position the tab in meshed engagement betweenadjacent teeth 1042 on the spindle gear 1040.

The control assembly 1010 further includes a socket 1080 adapted to matewith a tool operable to apply torque (e.g., an Allen wrench). With thisconfiguration, the socket 1080 could be used to apply torque to thecontrol gear 1060 and tab 1065. Specifically, once the biasing member1070 is compressed and the gears 1030, 1040, 1060, 1065 of each assembly1005, 1010 are aligned/meshed, torque may be applied to the uppersection 1052 of the control assembly 1010.

In operation, the control assembly 1010 begins in its normal position,in which the control gear 1060 and the tab 1065 are not meshed with thecollet gear 1030 and the spindle gear 1040, respectively. A tool isaxially inserted into the socket 1080 to seat the tool onto the socketkey. The tool drives the carriage 1050 axially along the shaft 1045until the gears become aligned. If necessary, the lower section 1055automatically rotates slightly to align the tab 1062 in meshedengagement with the teeth 1042 of the spindle gear 1040. Alternatively,a user may manually rotate the tool to align the gears. Rotating thetool causes the first section 1052 to rotate. The second section 1055,however, rotationally fixes the spindle 1015 as a result of the meshedengagement between the tab 1065 and the spindle gear 1040. Thus, thecollet nut 1025 rotates, while the spindle 1015 is held rotationally inposition. This axially moves the collet nut 1025 along the spindle 1015,opening and closing the collet 1020 to capture or release the bit (asdescribed above).

FIGS. 11-14 illustrate a rotary tool bit retaining system in accordancewith another embodiment of the invention. The bit retaining system 1100includes a bit holder 1115 secured to a spindle 1110 at one end, andwhich, in turn, secures a tool bit 1165 at an opposite end. The bitholder 1115 includes a threaded housing 1125, a wedged collet 1168, athreaded worm nut 1135, and a worm actuator 1140. The threaded housing1125 may be a generally cylindrical member that is releasablyconnectable to spindle 1110. The spindle 1110 includes a first/upperportion including a lock recess 1145 that engages the worm actuator 1140and a second/lower portion having an internal surface 1150 that tapersinward in the direction away from spindle 1110. The outer surface of thesecond/lower portion of the spindle 1110 is threaded.

The threaded worm nut 1135 includes an inner threaded bore 1155 andwormed gears 1160 on an outer/upper surface. A lower inner surface ofthe threaded worm nut 1135 includes an inwardly directed projection 1162for engaging wedged collet 1168. The wedged collet 1168 is generallycylindrically shaped with an outer tapered surface 1170 that is taperedin a direction toward spindle 1110. The outer tapered surface 1170 isdisposed opposite inner lock surface 1172 of wedged collet 1168. Thewedged collet 1168 also includes an outwardly facing recess 1175 in itsouter surface, which is engaged by the projection 1162 of threaded wormnut 1135. The wedged collet 1130 also includes an inner lock surface1172 against which a tool bit 1115 is frictionally secured.

The worm actuator 1140 includes a worm 1180 and a lock support 1182 andis pivotally secured to the rotary tool (e.g., a router (not shown)) viaa pivot pin PP (seen best in FIG. 12). The worm actuator 1140 is engagedwith the threaded worm nut 1135. FIG. 13 shows the worm actuator 1140 ina disengaged arrangement. A safety switch 1310 may be employed to ensurethat the router motor can only be energized when worm actuator 1140 isin its disengaged position. For example, in one embodiment, the safetyswitch 1310, 1320 may be closed in the disengaged position of wormactuator 1140. One or more switches may be used in various ways toemploy this safety feature.

Referring back to FIG. 11, the lock support 1182 may also include a lockprojection 1185 for projecting into the lock recess 1145 of the threadedhousing 1125. The function of the lock projection 1185 will be discussedbelow.

Referring to FIG. 12, the worm 1180, which includes a plurality of wormteeth 1210, is rotatably positioned on lock support 1182. The worm 1180may include a shaped recess 1220 exposed in an opening 1225. A tool canbe inserted into shaped recess 1220 and the user can turn the tool torotate worm 1180. Alternatively, as shown in FIG. 14, the worm 1180 mayinclude a keyless hand turnable member 1410 such as a knob. Inoperation, a user simply turns the hand turnable member 1410 to rotateworm 1180.

Referring back to FIG. 11, the tool bit 1163 includes a blade 1165 and ashaft 1190. The shaft 1190 is received in the inner lock surface 1172 ofthe wedged collet 1130.

In operation, a user inserts shaft 1190 of tool bit 1163 into wedgedcollet 1168. The user then insures that worm actuator 1140 is in theengaged position (FIG. 2). When the worm actuator 1140 is in the engagedposition, the worm teeth 1210 engage gears on threaded worm nut 1135.The user then rotates worm 1180 by inserting a tool into shaped recess1220 or by rotating keyless hand turnable member 1410. As a result, thethreaded worm nut 1135 rotates about the router's central rotationalaxis relative to worm 1180. To insure that the inner threads of threadedworm nut 1135 will rotate relative to the outer threads of threadedhousing 1125 against friction between the threads, the lock projection1185 is employed. In the engaged position, the lock projection 1185 isreceived into and interlocks with the lock recess 1145 of threadedhousing 1125. Because the worm actuator 1140 is not rotatable about thesame axis as that of the spindle 1110, this interlock prevents rotationof spindle relative to the rotor and, as such, prevents thesame-direction rotation of threaded worm nut 1135 and the threadedhousing 1125.

As inner threads of threaded worm nut 1135 rotate relative to the outerthreads of the threaded housing 1125, the threaded worm nut movesaxially along the spindle 1110, toward the router. Because the inwardlydirected projection 1185 engages outwardly facing recess 1175, wedgedcollet 1130 also axially translates in the direction of spindle 1110. Asthe outer tapered surface 1170 of wedged collet 1130 slides along theinner tapered surface 1150 of threaded housing 1125, the inner locksurface 1172 of the wedged collet 1130 moves toward the central axis ofrouter spindle 1110. This inner surface contacts the shaft 1190 of thetool bit 1163 to secure the tool bit in a manner that is axially alignedwith router spindle 1110.

While the present invention has been described in detail and withreference to specific embodiments thereof, it will be apparent to oneskilled in the art that various changes and modifications can be madetherein without departing from the spirit and scope thereof. Thus, it isintended that the present invention covers the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents. It is to be understood that termssuch as “top”, “bottom”, “front”, “rear”, “side”, “height”, “length”,“width”, “upper”, “lower”, “interior”, “exterior”, and the like as maybe used herein, merely describe points of reference and do not limit thepresent invention to any particular orientation or configuration.

We claim:
 1. A bit retaining system for retaining a bit in a rotarytool, the system comprising: a collet assembly including: a spindleoperable to rotate about a spindle axis, the spindle comprising aninternal channel and having a threaded external surface, the spindleincluding a plurality of gear teeth that define a spindle gear; a colletmounted within the internal channel of the spindle and operable toreceive a shank of the bit, the collet being configured to move axiallywith respect to the spindle; a collet nut including internal threads inthreaded engagement with the threaded external surface of the spindle,and restricting the axial movement of the collet with respect to thespindle, the collet nut having a plurality of gear teeth that define acollet gear; and a control assembly including: a carriage slidablymounted on a support post; a control gear rotatably connected to thecarriage so as to be able to rotate with respect to the carriage; and abiasing member that biases the carriage toward a first position, whereinthe carriage is configured to move from the first position, in which thecarriage is disengaged from the spindle gear, to a second position, inwhich the carriage engages the spindle gear, and wherein, when thecarriage is in the second position, a rotary force applied to thecontrol gear causes a corresponding rotation of the collet gear to drivethe collet nut along the spindle.
 2. The bit retaining system accordingto claim 1, wherein the control gear includes a plurality of teethadapted to mesh with the plurality of teeth of the collet gear.
 3. Thebit retaining system according to claim 1, wherein the biasing member isin the form of a compression spring.
 4. The bit retaining systemaccording to claim 1, wherein, the control gear is adapted to rotatewith respect to the carriage about an axis generally aligned with alongitudinal axis of the support post, and wherein the carriage movesaxially along a carriage axis from the first position to the secondposition.
 5. The bit retaining system according to claim 1, wherein thecontrol assembly further comprises a receptacle for receiving and matingwith a hand operated tool.
 6. The bit retaining system according toclaim 5, wherein rotating the hand operated tool applies the rotaryforce to the control gear.
 7. The bit retaining system according toclaim 1, wherein the control assembly is configured to selectivelyengage the spindle to prevent rotation of the spindle about the spindleaxis.
 8. The bit retaining system according to claim 1, wherein thecarriage includes a radially extending locking tab that extends radiallywith respect to a rotation axis of the control gear and that is seatablebetween adjacent teeth of the spindle gear.
 9. The bit retaining systemaccording to claim 1, wherein the collet includes fingers adapted tocollapse and expand around the shank of the bit.
 10. A bit retainingsystem for retaining a bit in a rotary tool, the system comprising: acollet assembly including: a spindle operable to rotate about a spindleaxis, the spindle comprising an internal channel and having a threadedexternal surface; a collet disposed within the internal channel andoperable to receive a shank of the rotary tool bit, the collet beingconfigured to move axially with respect to the spindle; a collet nut inthreaded engagement with the threaded external surface of the spindle,the collet nut restricting the axial movement of the collet with respectto the spindle, and having a plurality of gear teeth that define acollet gear; a spindle gear longitudinally spaced from the collet gearalong the spindle axis and including a plurality of teeth; and a controlassembly comprising: a support post including a plurality of guidenotches; a displaceable member including a base and a plurality of legsextending from the base, the displaceable member being slidably androtatably mounted on the support post allowing the plurality of legs toslide along the plurality of guide notches; and a control gear rotatablymounted to the displaceable member and supported on the plurality oflegs; wherein the displaceable member is configured to move from a firstgear position, in which the displaceable member is disengaged from thespindle gear, to a second gear position, in which the displaceablemember is engaged with the spindle gear, and wherein, when thedisplaceable member is in the second position, a rotary force applied tothe control gear causes a corresponding rotation in the collet gear todrive the collet nut axially along the spindle.
 11. The bit retainingsystem according to claim 10, wherein the control assembly furthercomprises a biasing member to bias the displaceable member to the firstgear position.
 12. The bit retaining system according to claim 10,wherein the displaceable member further includes a locking tab extendingfrom the base, the locking tab configured to mesh with teeth of thespindle gear and prevent rotation of the spindle.
 13. The bit retainingsystem according to claim 10, wherein in the first gear position, alocking tab is disengaged from the teeth of the spindle gear, and in thesecond gear position, the locking tab is seated between adjacent teethof the spindle gear.